Helical-spring-quenching device



Aug. 10 1926. v

W. J. MERTEN HELlG'AL SPRING QUENCHING DEVICE Filed March 5. 1921 f ENVENTOR Wi I/I'am, J Meren.

ATTORNEY Patented Aug. 10, 1926.

UNirsn STATES Partnrv erica.

WILLIAICI J'. MER'IEN, 0F PITTSBURGH, PENNSYLVANIA, ASSIG-NOR TO VVIESTDIG- HOUSE ELECTRIC & LIANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

HELICAL-SPRING-QUENCHING DEVICE.

Application led March 5, 1921. Serial No. 449,637.

This invention relates to quenching, more especially to the quenching of hollow bodies, such as helical springs used in railway rolling stock.

Considerable difficulty has been encountered in quenching helical springs in order to harden the same. It has been found that, when springs of this character are heated to a temperature above the critical point of the material and the spring placed in a quenching bath, the hardness of the various parts of the spring is not uniform. Apparently, the quenching or cooling in the medium is not uniform throughout and, generally, the outer surfaces of the coils of the springs are harder than the inner surfaces. This is probably due to a difference in the rate of cooling of the surfaces that sets up strains in the spring which cause failure thereof.

The present invention is designed to obviate this difficulty, it being among the objects `of this invention to quench hollow bodies, such as helical springs, in such manner as to avoid the non-uniformity of hardness which has hitherto resulted from quenching in liquid media and to provide a spring of this character in which substantially no strains are set up between the various parts thereof.

I have found that, when a hollow body, such as a helical spring, is heated to av high temperature and` then dropped into a bath of quenching fluid, such as oil, there is less circulation of oil in the interior of the spring than along its outer surfaces. Gas pockets are formed in the interior which tend to reduce the circulation of oil in the interior of the spring and thus further retard the hardening process.

I have overcome these di'liiculties by providing a system in which the quenching fluid, such as oil, is forced simultaneously through the interior of the spring and over the outer surface thereof in order to cause uniform and simultaneous hardening of the entire spring. By providing such a system, I have formed springs of uniform hardness throughout and have greatly diminished the danger of breaking of such springs in service and have prolonged the life and 'efficiency thereof.

In practicing my invention, I provide a bath of quenching fluid, such as oil, and suspend therein a suitably shaped member adapted to hold a spring to be quenched in a horizontal position. I further provide a conduit having a series of openings and place it above the spring to be quenched so that liquid flowing from said openings flows over the exterior of the spring. A second conduit is so placed that liquid owing therefrom passes through the interior of the sprino'. Both conduits are connected to a source of pressure which forces the oil therethrough.

In the accompanying drawings forming a part hereof and which illustrate a single embodiment of my invention,

Fig. 1 is a vertical, sectional view through a container embodying my invention;

Fig. 2 is a side elevational view of the quenching means, and

Fig. 3 is afront view of the spring holder.

I provide a container 1, preferably open at the top and filled with quenching fluid 2 of any suitable kind, usually oil. A pipe 3, connected to a source of oil under pressure, leads into container 1 and has a branch or T to which is connected a nipple 5 having a valve 6 connected thereto and terminating in a short pipe 7. To the other opening of the T is secured a valve 9 having a pipe S connected thereto, said pipe terminating at 10 in a horizontal member, the end thereof being closed as shown at 11. Openings 12 are formed in the lower portion of horizontal section 10.

Directly below said portion 10 isV placed a member 13 of scoop shape having a series of openings 14. and secured to a frame 15 having a bend 16 of substantially the form of an inverted U. A co-operating hoolr member 17 is suspended from a suitable support 18 secured to the container 1. A pipe 19 leads from th-e bottom of the container to the source of pressure and aids in the circulation of the oil.

' The operation of my device is as follows: Oil is caused to iiow into pipe 3 under pressure produced by a pump or other suitable means (not shown) and liows through the T l and valves 6 and 9 and outl through pipes 7 and 8. The openings of the valves are regulated to give the desired flow. A spring 2O to be quenched is placed upon the member 13 .and is lowered into the bath of quenching fluid, being suspended therein from hook member 17. Oil, flowing from openings 12, descends upon the exterior of the spring while oil flows from the open end of pipe 7, which is centrally located with respect to the interior of the spring', thus causing a rapid circulation of oil on all sides of the sprinO'. @penings 1d in member 13 serve to allow a free circulation of oil along the underside of the spring and, at the .same time, the support of member 13 prev-ents distortion of the spring which would talie place if it were not properly held in position during the quenchingoperation.

lt will be apparent that my invention provides a novel method of quenching hollow bodies, such as spiral springs, in that both the exterior and the interior thereof are quenched simultaneously. TWhen the oil is caused to flow under pressure, the quenching operation is expedited and the efficiency of the process is increased. By causing uniform quenching, of the spring, it becomes of uniform hardness on all sides, and the danger of the spring breaking` in service is minimized.

I have found that the direction of the two streams of the incoming cooling fluid n of ' temperature at and in the vicinity of the spring. rllhis may be materially increased by having' the horizontal pipe 10 at approximately the level of the oil and the spring, approximately six inches below the surface of the oil. This results in a spring which is hardened uniformly and greatly strengthened by reason of the minimizing of strains induced in the spring` by the hardening operation.

I claim as my invention:

1. A method of quenching a hollow body which comprises simultaneously directing' streams of quenching fluid radially and axially on said body.

2. A method f quenching; a helical sln'inp; which comprises causing quenching fluid to flow into contact with both the interior and the exterior thereof.

3. A method of quenching a helical spring which comprises causing quenching fluid to flow into contact with both the interior and the exterior' thereof Simultaneously.

el.. A method of quenching' a helical spring which comprises supporting' the same longitudinally and causing` quenching fluid to flow into contact with both the interior and the exterior thereof.

A method of quenching' a helical spring which comprises placing the same on perforated .support and causing quenching fluid to flow into Contact with both the interior and the exterior thereof.

G. Apparatus for quenchingv hollow bodie comprising` a container for quenching,l fluid, a plurality of conduits for circulating said fluid and means for holding a body to quenched in the path of curr-ents so ren-crated, one of said conduits being positioned at the surface of said fluid.

i'. Apparatus for quenching hollow bodies comprisinga container for quenchingfluid, a plurality of conduits connected to a common source for circulating said fluid and means for holding' a body to be quenched in the path of currents generated, one of said conduits being horizontal and positioned at the surface of said fluid.

8. Apparatus for quenching` hollow bodies comprising a container for quenching' fluid, a plurality of conduits for circulating said fluid and means for holdingl a body to be quenched in the path of currents so generated, said means comprising d perforated member of scoop shape and means for suspending the same in said container.

9. Apparatus for quenching' hollow bodies coniprising a container for quenching fluid, a plurality of conduits for circulating` said fluid, means for holding a body to be quenched in the path of currents so generated, said means comprising a perforated member of scoop shape and iii-cans for suspending the same in said container, one ol said conduits being' adapted to circulate said fluid through said bodyv and the other to force the same over said body.

In testimony whereof, l have hereunto subscribed my name this 26th day of February 1921.

VVILLlAlI J. MERTEN 

